DOI: 10.2478/cjf-2022-0019
Original scientific paper
GROWTH AND MORTALITY, RECRUITMENT, AND EXPLOITATION RATE OF FRINGESCALE SARDINELLA (Sardinella fimbriata, Valenciennes 1847 ) IN ROTE ISLAND, SAVU SEA
2022, 80 (4) p. 189-196
Fanny Ginzel, Diah Wijayanti, Subagiyo Subagiyo, Agus Sabdono
Abstract
Fringescale sardinella (Sardinella fimbriata, Valenciennes 1847) is one of the largest fishery resources in the Savu Sea. This species is one of the economically important fish resources found in Savu waters. The increasing demand comes along with the high economic value of this fish makes it one of the main targets of capture. The intensive utilization of this species might result in overfishing. Hence, the purpose of this study was to investigate the population dynamics of fringescale sardinella in Rote Island, Savu Sea through length-frequency samples collected for consecutive 4 months (August to November 2021) from fishermen's catches. A total of 1095 fish sampled from Rote Island, Savu Sea were assessed and showed the total length (TL) range from 90 mm to 157 mm. Further, the data were analyzed using FISAT II Software, and gave the following results: the length-weight relationship was W= 0.0004L2.2523. While, the negative allometric growth pattern and growth equation was Lt = 165.26 (1 - exp1,500 (t + 0.0585)). The age of S. fimbriata consisted of 1-2 cohorts. Recruitment of S. fimbriata in Rote Island, Savu Sea occurred throughout the year with the highest peaks in May and August. The size of the first caught fish (Lc) was 96.98 mm TL. The total mortality rate (Z) was 2,41 yr-1, natural mortality (M) was 1.45 yr-1 and fishing mortality (F) was 0.97 yr-1. The exploitation rate of S. fimbriata is estimated at 0.40 yr-1, this implies that the stock does not exceed the optimum exploitation rate (E = 0.5) or overfishing has not occurred in the Savu Sea. Nevertheless, this result study obtained is sufficiently robust to anticipate that the unprecedented overexploitation of the S. fimbriata in Rote Island, Savu Sea has nearly occurred. Therefore, regular monitoring and surveillance of surface gillnet fishing gear are urgently needed.
Keywords
length-weight relationship, population dynamics, natural mortality, fishing mortality